A conventional compressor includes, in its casing, a compression mechanism and a drive shaft for driving the compression mechanism. The drive shaft has an oil supply hole which is opened through its outer peripheral surface to supply oil to its own bearing surface. An oil supply groove communicating with the oil supply hole is arranged on the outer peripheral surface of the drive shaft so as to extend along the shaft (see, e.g., Japanese Unexamined Patent Publication No. H9-228971). In the compressor of Japanese Unexamined Patent Publication No. H9-228971, the oil supply passage is formed inside the drive shaft and extends in the axial direction. The oil accumulated in an oil reservoir inside the casing is supplied from the oil supply passage to the bearing surface through the oil supply hole and the oil supply groove.
As illustrated in FIGS. 6A and 6B, in the compressor of Japanese Unexamined Patent Publication No. H9-228971, the oil supply passage (101) is formed through the middle of the drive shaft (100) and extends in the axial direction. The oil supply hole (102) connected to the oil supply passage (101) is formed to extend perpendicularly to the oil supply passage. An oil supply groove (103) is provided as a recessed groove on an outer peripheral surface of the drive shaft (100) and extends in the axial direction. This oil supply groove (103) also serves as an oil discharge passage for supplying oil to another bearing provided above the bearing (105) shown in the drawing.